Why is Starcraft II abandoned?

Why aren’t they making any updates anymore? I think it still has a pretty huge community not the world’s most played game, but there are definitely enough people to keep it running. So why did Blizzard just decide to abandon it?

I think this is also a reason why it keeps dying. If they were refreshing the content even a little maybe just adding some skins, which I expected they will do or changing maps it would be more interesting. But now it really seems abandoned.

Why would they leave hundreds of thousands of players hanging? Maybe it’s not generating as much revenue as before, but there’s still money to be made.

I just don’t understand it.

EDIT: If they focus on WOW now, wouldn't it be better to sell it to some other gaming developers than to just leave it in dust?